IR 05000397/1996016
ML17292A585 | |
Person / Time | |
---|---|
Site: | Columbia ![]() |
Issue date: | 11/01/1996 |
From: | WEBRING R L WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
References | |
GO2-96-216, NUDOCS 9611140044 | |
Download: ML17292A585 (40) | |
Text
M&kWeLREGULATORY INFORMATION DISTRIBUTION SYSTEM(RIDS)ACCESSION NBR:9611140044 DOC.DATE:
96/11/01NOTARIZED:
NODOCKETFACIL:50-397 WPPSSNuclearProject,Unit2,Washington PublicPowe05000397AUTH.NAMEAUTHORAFFILIATION
~~~BRING,R.L.
Washington PublicPowerSupplySystemECIP.NAME RECIPIENT AFFILIATION DocumentControlBranch(Document ControlDesk)
SUBJECT: ProvidesaddiinfotoassistNRCinevaluating issuesininsprept50-397/96-'16
&NOV.DISTRIBUTION CODE:IE01DCOPIESRECEIVED:LTR ENCLSIZE:TITLE:General(50Dkt)-Insp Rept/Notice ofViolation ResponseNOTES:RECIPIENT IDCODE/NAME PD4-2PDCOPIESLTTRENCL11RECIPIENT IDCODE/NAME COLBURN,T COPIESLTTRENCL11TEIINTERNAL:
ACRSAEODTTCILE~CTERDRCH/HHFB NRR/DRPM/PERB OEDIRRGN4FILE0122111111111111AEOD/SPD/RAB DEDRONRR/DISP/PIPB NRR/DRPM/PECB NUDOCS-ABSTRACT OGC/HDS31111111111110Y;EXTERNAL'ITCOBRYCEIJH1,111NOACNRCPDR()~$~$)i&tL~Y(YJ'Hct11D0jUE.NNOTETOALL"RIDS"RECIPIENTS:
PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATION REMOVEDFROMDISTRIBUTION LISTSORREDUCETHENUMBEROFCOPIESRECEIVEDBYYOUOR'YOURORGANIZATION',
CONTACTTHEDOCUMENTCONTROLDESK(DCD)ONEXTENSION 415-2083TOTALNUMBEROFCOPIESREQUIRED:
LTTR19ENCL19
/'
tiWASHINGTON PUBLICPOWERSUPPLYSYSTEMP.O.Box968~3000GeorgeWashington Way~Richland, Washington 99352-0968
~(509)372-5000November1,1996G02-96-216 DocketNo.50-397U.S.NuclearRegulatory Commission Attn:DocumentControlDeskWashington, D.C.20555Gentlemen:
Subject:WNP-2,OPERATING LICENSENPF-21NRCINSPECTION REPORT96-16,ADDITIONAL INFORMATION Reference:
LetterdatedSeptember 12,1996,KEBrockman(NRC)toJVParrish(SS),"NRCInspection Report50-397/96-16 andNoticeofViolation" TheSupplySystemattendedapredecisional enforcement conference onOctober22,1996,intheRegionIVofficesregarding-the apparentviolations identified inthereferenced inspection report.Basedonthediscussion thatoccurredrelativetotwooftheapparentviolations, theSupplySystemisproviding additional information toassistthestaffinevaluating theseissues.Attachment 1liststhecorrective actionstakenorplannedasaresultofthereactivity management issuesindicating miscalculation oftheestimated criticalpositionasdiscussed inthereferenced report.Thesecorrective actionswereidentified aspartoftheresolution ofWNP-2ProblemEvaluation Report(PER)296-0522issuedonJune27,1996.TheSupplySystemconsiders themiscalculation tobeofsignificant concernand,inresponse, hasidentified abroadspectrumofcorrective actionstopreventrecurrence.
Attachment 2providesatimelinefortheapproachtocriticalactivities.
Thistimelineisconsistent withthediscussion providedatthepredecisional enforcement conference.
Theaccuracyhasbeenverifiedbasedoncontrolroomrecordsandwrittenandverbalstatements providedbytheindividuals involved.
Attachment 3containssignedstatements usedtogeneratethetimeline, IgEor'AAttachment 4providesabriefsynopsisofavideocassette thatisincludedforyourreview.Asdiscussed atthepredecisional enforcement conference, a"TimeOut"washeldwithWNP-2employees onJuly23,1996toaddressconcernswithrecentstationperformance.
96iii40044 9hilOiPDRADOCK050003978PDR1300:40(y)...~./c;;(,~r.'~'
PageTwoNRCINSPECTION REPORT96-16,ADDITIONAL INFORMATION Attachment 5containstheIncidentReviewBoard(IRB)reportforPER296-0522, assessing criticality achievedpriortominimumestimated criticalposition(ECP).ThepurposeoftheIRBistoimmediately investigate planteventswhereperformance issuspected tobeamaincontributor, orthoseeventswithsignificant safety,economic, processorregulatory impact.TheIRBprovidestheinitialinformation gathering andisonlyaninputtotheformalrootcauseaspartofthePERprocesses.
Thisreporthasnotbeencertified foraccuracyandisbeingincludedforyourinformation.
Thereporthasbeenredactedtoremoveindividual's namesforprivacypurposes.
TheSupplySystemregretsnothavingthisinformation readilyavailable atthepredecisional enforcement conference.
Weappreciate theopportunity toprovidethisinformation atthistime.Ifyourequireadditional information pleasecontactmeorD.A.Swankat(509)377-4563.
Respectfully, R.L,Webring~~VicePresident, Operations Support/PIO MailDropPE08Attachments Reactivity Management Corrective ActionsTakenorPlannedApproachtoCriticalTimelineSignedStatements TimeoutVideocassette IncidentReviewBoardReportCriticality CC:J.Lieberman
-NRR(withvideocassette)
LJCallan-NRCRIV(withvideocassette)
KEPerkins,Jr.-NRCRIV,WalnutCreekFieldOfficeNSReynolds-Winston&StrawnTGColburn-NRRDLWilliams-BPA/399NRCSr.ResidentInspector
-927N NRCINSPECTION REPORT96-16,ADDITIONAL INFORMATION Attachment 1Page1of5REACTIVITY MANAGEMENT CORRECTIVE ACTIONS1)Developprocedure tocalculate Estimated CriticalPositions (ECP).Procedure PPM9.3.6wasissuedonJuly19forthispurpose.2)Evaluatesignificant differences betweenversionsofPOWERPLEX forchangeswhichprovideincreased optionselection orchangesinthedefaultsettings.
Providetrainingon.differences.
Differences betweenversionswereevaluated andtrainingwasprovidedonJuly30andAugust8.3)IssuealettertoSiemensPowerCorporation (SPC)explaining thesignificance oftheeventandrequesting anexplanation.
Requestcorrections toPOWERPLEX UsersManualandrequestSPCtoevaluatetheneedtoinformotherusersofthesituation.
AletterwasissuedtoSPConSeptember 23.4)Evaluatethepossibility ofdeveloping toolstoanalytically estimatecriticality basedonsubcritical multiplication.
Investigate andevaluateindustrypracticetoexplorethepossibility ofimplementing alternate meansofmonitoring theapproachtocriticality atWNP-2andimplement theenhancements.
Providetheconclusion oftheevaluation toEngineering Management.
Actionisscheduled tobecompletebyNovember20.5)Evaluatepersonnel performance issuesbothnegativeandpositiveintheperformance evaluations oftheindividuals involved, Issuesweredocumented inperformance evaluations ofindividuals involved-Actionwascompleted onSeptember 25.6)EvaluatetheeffectsoffrequentturnoveroftheReactorEngineering Supervisor andthepotential impactontheconsistency andqualityofsupervision.
Providerecommendations toReactor/Fuels Engineering Management.
Anevaluation wasperformed andsuccession planningfortheReactorEngineering groupwillbeaformalexpectation fortheReactorEngineering Supervisor andFuelsManager.Thisactionwascompleted onSeptember 18.7)EvaluatethepracticeofhavingtheSupervisor ofReactorEngineering alsoworkingonshiftasadutyStationNuclearEngineer(SNE).Evaluatedifferent strategies thatmayprovidethesupervisors withcurrenttrainingandexperience whileperforming assupervisor aswell.Actionwascompleted onSeptember 18.8)Provideeventdiscussion, overview, andLessonsLearnedtrainingduringupcomingSNEcontinued training.
Trainingwasconducted onJuly30andAugust NRCINSPECTION REPORT96-16,ADDITIONAL INFORMATION Attachment 1~Page2of5REACTIVITY MANAGEMENT CORRECTIVE ACTIONS9)ProvideformaltrainingonthecurrentversionofPOWERPLEX forReactorFuelspersonnel relatingnewfeatureswithpractical usesofnewoptions.Trainingwasconducted September 10,11and12.10)Identifywhichplantevolutions shouldhavesecondorderSNEreviewandtransmittotheReactorEngineering organization.
Procedure PPM9.3.9,"ControlRodWithdrawal SequenceDevelopment
&Control,"
wasreviewedtoidentifyevaluations requiring secondreviewbyaqualified ReactorEngineer.
Nochangeswererecommended andtheactionwascompleted onOctober28.11)Reviseprocedure PPM3.1.2toreinforce themanagement expectations forcontrolofreactivity manipulations.
Procedure PPM3.1.2hasbeenupdatedtoincludemanagements expectations onreactivity control(i.e.,instruction wasaddedtostopcontrolrodwithdrawal ifitisanticipated thatthecorewillnotgocriticalwithintheECPlimits).Actionwascompleted onJuly3.12)Discussrelevantaspectsofindividual performance andprovidecounselling totheSNEsandFuelDesignEngineers directlyinvolvedwiththemiscalculation oftheECP.OnJune27and28theSupervisor, FuelsDesignandManager,Reactor/Fuels Engineering providedcounselling tothoseindividuals involvedontheneedforconservative decisionmakingandimprovedverticalcommunication.
13)Discussrelevantaspectsofindividual performance andprovidecounselling totheOperating crewmembersdirectlyinvolvedwiththeECPevent.TheActingOperations Managerdiscussed theECPeventwiththeOperating crewmembersdirectlyinvolved.
Counselling wasgivenontheneedforconservative decisionmakingandimprovedverticalcommunication.
14)Discusstechnical andpersonnel performance aspectsofmiscalculation oftheECPwiththeSNEsandotherEngineering personnel notdirectlyinvolvedtoensurecommonunderstanding ofcausesandperformance expectations.
OnJune28aTimeOutwasheldtoensureunderstanding ofcausesandperformance expectations.
InadditionanInteroffice Memorandum fromareactorengineerdatedJuly11toManagement providedadditional information ontheECPcalculation process.15)Discusstechnical andpersonnel performance aspectsofmiscalculation oftheECPwiththeOperations crewnotdirectlyinvolvedtoensurecommonunderstanding ofcausesandperformance expectations.
TheActingOperations Managerconducted trainingforOperations personnel onJuly31,August1,2,and1 NRCINSPECTION REPORT96-16,ADDITIONAL INFORMATION Attachment 1Page3of5REACTIVITY MANAGEMENT CORRECTIVE ACTIONS16)ConductTime-outsessionswithotherstationpersonnel regarding causesofmiscalculation oftheECPeventandmanagement's expectation.
OnJune28aBroadcast messagewasissuedadvisingManagersandSupervisors toconductaTimeOutonthisissue.17)Reviewandreviseifnecessary PPM1.4.14toincludeformaltrainingonfuturegeneralversionsofPOWERPLEX forReactor/Fuels Engineering personnel relatingtonewfeatureswithpractical usesofnewoptions.Theprocedure wasreviewedandnochangesweredeemednecessary butanInteroffice Memorandum wasissuedtoReactor/Fuel personnel requesting thateachengineerreviewtheportionsoftheprocedure whichdealwithtrainingandtheirresponsibilities inthatarea.Actionwascompleted onOctober11.18)Provideevidenceofaself-assessment doneonreactivity management.
Followuponrecommendations byinitiating additional corrective actionplans(CAPs)ifnecessary.
Reviewwasconducted andreportwasissuedJuly29.Recommendations werefollowedupbyinitiating CAPs22through29(items23through30below).19)Conductindependent reviewbySPCtoidentifythedifferences introduced withthenewversionofPOWERPLEX andidentifywhatsafetyissueswereassociated withtheECPincident.
LetterwassenttoSupplySystemonJuly18fromSPCwhoconducted theindependent review.ThePOWERPLEX inputdeckandrunoptionswerereviewedandthechangesmadeforCycle12weredetermined tobecorrect.Nosafetyissueswereassociated withtheECP.20)Providerefresher trainingtoOperations Crewregarding therelativeeffects,e.g.,magnitude, durationonreactivity ofXenon,moderator temperature andothersignificant physicalparameters.
Actionisscheduled tobecompletebyNovember30,1996.21)Providerefresher trainingtoReactor/Fuels Engineering regarding therelativeeffects,e.g.,magnitude, durationonreactivity ofXenon,moderator temperature andothersignificant physicalparameters.
Actionwascompleted onOctober8.22)Provideevidenceofcommunicating thefindingsoftheReactivity Management Teamconcerning trainingandqualification ofvendors,useofverbalcommunications requirements, procedural enhancements totheadjustable speeddrive(ASD)startuptestprocedure, andconservative decisionmakingexamplesfromtheeventstoinvolvedEngineering staff,andmanagement oversight/test directors andanyothergroupsidentified bymanagement.
Alltheindividuals identified bytheTeamweretrainedduringtheTimeoutconducted June2 NRCINSPECTION REPORT96-16,ADDITIONAL INFORMATION Attachment 1Page4of5REACTIVITY MANAGEMENT CORRECTIVE ACTIONS23)Provideevidenceofcommunicating thefindingsoftheReactivity Management Teamconcerning trainingandqualification ofvendors,useofverbalcommunications requirements, procedural enhancements totheASDstartuptestprocedure, andconservative decisionmakingexamplesfromtheeventstoinvolvedOperations staff,andmanagement oversight/test directors andanyothergroupsidentified bymanagement.
-'rainingwasconducted onJuly31,August1,2,and16.24)Reviewandreviseifnecessary procedures toclearlydelineate thoseactivities andevolutions whichhavethepotential foraffecting reactivity.
Providetheexpectations forlicensedoperators commandandcontrolduringthoseactivities andevolutions Procedures PPMs1.3.1and1.3.2wererevisedandincludeoperatorexpectations.
Actionwascompleted onOctober16.25)26)Reviewandreviseifnecessary procedures toclearlydefineapproachtocriticality toestablish aconsistent understanding withandbetweenoperating crews.Providespecificexpectations ofactivities whichshouldbeavoidedthatcandistractoperators andsupervisors involvedinreactorstartupduringapproachtocriticality.
Itshouldbeclearlydelineated thatindividual turnover, shiftmeetingsinthecontrolroom,andsurveillance testingaredefinitely includedinactivities whichshouldbeavoided.Procedure PPM1.3.1wasrevised.Actionwascompleted onOctober17.Benchmark otherutilities todetermine ifothernuclearpowerplantsareproviding theReactorOperators withmoredataconcerning estimated criticality point.Baseduponresultsofthisbenchmarking andtheexperiences atotherfacilities, considersupplying minimumandmaximumbracketing ofECPtotheReactorOperators.
CROswillbeprovidedwiththeECPhi/lowband.Actionwascompleted onOctober16.27)Provideevidenceofenhancing trainingforreactorstartuptoincludeinformation andexpectations for:1)periodicpausesduringrodwithdrawal toallowstabilization ofneutronlevel;2)consistent interpretation ofdatatodefineapproachtocriticality; 3)instrument and/orequipment failureresponses; 4)inaccurate estimated criticalconditions calculations; and5)preventing distractions.
Actionisscheduled tobecompletebyJune15,1997onoperations rotaingtraining.
28)Developsimulator scenarios toallowoperators toexperience theadverseconsequences thatresultfrominstrument failuresorECPerrors.Thescenarios shouldreinforce theneedforconsistency fromcrewtocrewfordefiningandestimating theapproachtocriticality andresponses tominimizedistractions duringthattimeperiod.Actionisscheduled tobecompletebyJune15,1997onoperatings rotatingtrainin NRCINSPECTION REPORT96-16,ADDITIONAL INFORMATION Attachment 1Page5of5REACTIVITY MANAGEMENT CORRECTIVE ACTIONS29)ReviewPPM3.1.2toincludetherequirement toconsidertheapplicability ofTechnical Specification 3.1.2whenevercriticality occursoutsideminimum/maximum ECPband.PPM3.1.2wasrevisedonSeptember 25.30)Reviewproblemsconcerning verticalcommunication ofissuessuchasthoseevidenced in'theECPerror,anddevelopcorrective actionstoensurepropersupervisory andmanagement notification ofconcernsandproblems.
June28TimeOutclosedthisactio NRCINSPECTION REPORT96-16,ADDITIONAL INFORMATION Attachment 2Page1of1APPROACHTOCRITICALTIMELINETIMELINEFEVENT0315Controlrodpullforreactorstartupcommences.
0533IRMCdeclaredinoperable 0542IRMCLCOsheetcompleted
-0605-OncomingControlRoomSupervisor (CRS)beginsturnoverwithoffgoingCRSatCRSdesk.-0620--0625-OffgoingCRSapproaches P603todirect"StuckRodFull-In"procedure.
AfterstuckrodisresolvedthetwoCRSscommencecontrolroompanelwalkdown.
OncomingCRSlooksatSRMrecorderduringwalkdownandseesnoindication ofimminentcriticality.
-0635--0640-BothCRSsreturntoCRSdesktocontinuetheirturnover.
ShiftTechnical Advisor(STA)tellsCRSsthattheyweregettingclosetocriticality.
-0645--0647-ControlRoomOperator(CRO)announces criticality isimminent.
TheCRSsimmediately completetheirturnoverandapproachP603.TheoncomingCRSannounces totheCROandSTAthatheistheReactivity Manager.StationNuclearEngineer(SNE)andCRSreviewtheestimated criticalposition(ECP)andobservecountrate.CRSreviewsPPM3.1.2statement whichstates"ifthecriticality isachievedpriortominimumECP,commenceshutdownbyinserting rodsinreversesequence."
CRSinformsSTAandCROthattheyarefourpullsheetpagesawayfromECPanddirectsthatrodpullbehalted.-0650-CRSinformstheShiftManager(SM)ofthesituation andtheydiscussthestatement inPPM3.1.2regarding criticality outsideECPlimits.CRSrecommends commencing rodpulltorecordthecountrateatcriticality andthenshuttingdown,asdirectedbyPPM3.1.2.-0700-SMaskedCRSifconductoftheshiftbriefingwilldistractthepersonnel atP603.TheCRSstatesthattheywillnotbedistracted andwillstayfocusedontherodpull(theSTAandCROwereholdingover,andtheCRSshadcompleted theirturnover).
07050712Criticality isachievedandcountrateisrecorded.
Shutdowniscommence NRCINSPECTION REPORT96-16,ADDITIONAL INFORMATION Attachment 3SIGNEDSTATEMENTS To:From:WhomItMayConcern.CharlesTownsendRe:NRCInspection Report50-397/96-16, specifically inregardstotheECPdiscussion.
Iwastheoff-going CRSasdescribed inthesubjectreport.TheReactivity Management discussions ofPPMs1.3.1and3.1.2werebriefedbymetotheROandSTA/SNEswhoparticipated inthepulltocriticality.
Itwasunderstood thatthereactorwouldbeshutdownifitwentcriticalbeforetheECPwindow.ItistruethatIthoughtthatDaleAtkinsonknewofthecontentsoftheECPMemobecauseitwasaddressed toDale.Iwasunawareofthedifficulties andconcernsthattheSNEshadinregardstotheECPcalculation.
Itsimplywasnotdiscussed withmeonthatnight.Ispentapproximately 2.5hoursatthebeginning ofthepulltocriticalatP603withtheROandSTA/SNEpullingrods.Iwasverifying thattheyconducted themselves withintheprocedures, briefs,andmanagement expectations aslaidoutinPPMs1.3.1,3.1.2,andtheOI-9forcontrolrodmovement.
Theconductofthecontrolroomstaffwasexemplary asdocumented inthesubjectOI-9s.Thereport,section01.2b.(3)
saysthatIspentthemajorityofmyattention andfocusfrom0533untiltheendofturnoveronactivities otherthanthepulltocriticality.
DuringthetimethatIwasfillingouttheLCOsheetIwasfocusedontheLCOthemajorityofthetime.LCOlogentry1682showsIRM-CInopat0533andsignedassuchbymeandtheShiftManagerat0542.Themajorityofmyattention andfocuswasonthepulltocriticality fromthattimeon;Ididspendtimearranging forturnoverandorganizing theCRSworkload, butspentmostofmytimereviewing therodpull.Thiswastrueduringtheactualturnovertimeaswellbecauseitwasthemaintopicdiscussed duringturnover(therewasnotmuchelsetodiscuss).
Section01.2b.(4)
saysthattheCRSdidnotstopturnoveraftertheSTAtoldthemthereactorwasclosetogoingcritical.
WedidstoptheturnoverandwereattheP603withinabout2minutes.Iattendedtheon-coming CRSduringthediscusions atP603andatnotimedidheappearsurprised oranythingtosupportthathe,'...suddenly observedthecondition oftheplant...'.
IlearnedagreatdealabouthowtobetheCRSandReactivity Managerfromthiseventandthediscussions andcoachingdirectedtowardsmyactions.Withperfecthindsight Iwouldnothaveconducted theCRSturnoverasitwasdone(eitherstoptherodpullorwaittoturnoveraftercriticality).
BettercommandandcontrolpracticewouldhavebeentoasktheSNEsnumerousquestions abouttheECPMemo.TheLCOsheetcanbefilledoutformyreviewbysomeoneelsefamiliarwiththeLCOcomputerprogram.TheCRS/Reactivity Managerisresponsible forallcontrolroomactivities, especially apulltocriticality, andmusttherefore beespecially vigilantineverystepoftheprocess.AlthoughIbelievewedidagoodjoboffollowing procedures andsafelybringingthereactorcritical, Icouldhavebeenmorediligentinobserving thepulltocrititcality inthelaststagesandmoreconservative indirecting activities basedontheprocedural guidance.
Ifthereareanyunanswered issues,pleasecallme.ResPectfullyy-.
CharlesTownsend WASHINGTON PUBLICPOWERSUPPLYSYSTEMPO.Box968~3000GeorgeWashington Way~Richland, Washington 99352-0968
~(509)372-5000To:AndyLangdonFrom:DonHughesThisstatement isbeingwrittenatyourrequesttogivemyanswerstosomeapparentdiscrepancies documented inNRCInspection Report50-397/96-16 asrelatetotheearlycriticality eventofJune27,1996.Thisismyrecollection oftheeventsastheyoccurred, inanswertothosesectionsofthereportyouhaverequested Ilookat.OnJune27,1996IarrivedtotheControlroomatWNP-2atapproximately 0605torelievetheCRS.AsIalwaysdo,Iwenttothekitchenandput.awaymylunch,andgotacupofcoffee.IthenreturnedtotheCRSdeskandstartedreviewing theprior48hoursofControlRoomlogssinceIhadnotbeenonWatchforseveraldays.Theoff-going CRSwasattheCRSdeskfillingoutaninopsheetforanIRMdetectorthathadapparently failedduringStartup.AfterIfinishedreviewing thelogs,theoff-goingCRSstartedtoturnovertometheeventsofthepreviousnight,thisincludedastatement thataPlantStartupwasinprogress.
Thiswasapproximately 0620,andatthattimetheoffgoingCRSwenttotheCROdesktodirectthe"Stuckrodfullin"procedure astheCROhadinformedhimtheyhadarodthatwouldnotmoveatnormalCRDdrivepressure.
Therodwasmovedwithraiseddrivepressure, drivepressurewasreturnedtonormal,andtheoffgoingCRSreturnedtomeandwecommenced ourControlRoomPanelwalkdown.Onpage6oftheNRCreportinparagraph (5)itstatesthat"DuringtheControlRoomSupervisor turnoverwalkthrough ofthecontrolboardpanels,theOncomingCRSsuddenlyobservedthecondition oftheplantandsourcerangemonitorneutronlevel.ThereactoroperatorstatedthatCriticality wasimminentThisactiondidnotoccurasdescribed, Ididlookatsourcerangemonitorsduringthecontrolboardwalkdownbutdidnotrecognize anyimminentcondition andtheCROdidnotstatethatCriticality wasimminentuntillaterafterthewalkdownofthepanelswascompleteandbothCRS'swerebackattheCRSdeskcompleting theturnover.
Onpage5oftheNRCreportinparagraph (4)itstatesthat"atthetimeofturnovertheSTAadvisedbothCRS'sthattheplantwasclosetogoingcritical" andthattheCRS'sdidnotstoptheirturnoverwhencriticality wasimminent.
TheoffgoingCRSandmyselfwereattheendofourturnoverandwerejustabouttoreviewtheStartupprocedure 3.1.2whentheSTAinformedusthatweweregettingclosetocriticalit WASHINGTON PUBLICPOWERSUPPLYSYSTEMPO.Box968~3000GeorgeWashington Way~Richland, Washington 99352-096S
~(509)372-5000TheoffgoingCRSacknowledged this,theSTAwentbacktotheCROdeskandstartupcontinued, approximately 1and1/2minlaterasIwasreviewing PPM3.1.2theCROpullingrodsturnedandinformedmethatCriticality wasimminent.
ItoldtheoffgoingCRS"Ihavenofurtherquestions, IrelieveyouasCRS"pickedupthestartupprocedure andimmediately wenttotheCROdesktomonitortheapproachtocriticality.
IinformedtheCROandSTAthatIwasnowtheReactivity Managerandopenedthestartupprocedure tolookattheECP.Ibelievethisaddresses page5paragraph (4),page6paragraph (5)andpage7paragraph (4).ItwasatthistimethattheSNEcametomysideandaskedifIknewwhattheMinimumAllowable CriticalPositionwas,ItoldhimIwasjustlookingatitandhehadmegototheSNEcomputertoshowmethatwewere4pagesfromtheminimumallowable criticalposition.
IreturnedtotheCROdesk,observedSRMcountsandaskedtheSTAandCROiftheywereawareoftheMinimumAllowable Criticalposition, theCROstatedhewasnotsinceINPOgoodpracticerecommends henotbeinformedoftheECPorMinimumAllowable positions.
TheSTAstatedthathehadseenthepositions buthadthenputhiscopyoftheECPintheSTAdesksoasnottoallowtheCROtoseethem,andhedidnotrememberwhatitwas.IinformedtheCROandSTAwewere4pagesfromtheMinimumAllowable positionandstoppedthemfrompullinganymorerods.IthenwentintoinformtheShiftManageroftheproblemwiththeECP.Isuggested tohimthatsincePPM3.1.2statedthat"ifthereactorgoescriticalpriortotheMinimumAllowable CriticalPosition,"
stoppullingrods,informtheCRSandhewilldirecta'shutdown, andwewerenotcriticalbythedefinition in3.1.2,thatwecontinuethestartuptoallowustorecordthelogreadingsnormallytakenatcriticality forrecordpurposeseventhoughIwascertainwewouldgocriticalpriortotheMinAllowCritPosition.
IbelievedheagreedwithmeandwentbacktotheCROdeskandreviewedthestatements regarding criticaliy occurring priortotheminallowpositionornotoccurring bythemaxallowpositionwiththeSTAandCROanddirectedthemtocontinuetheStartuptoallowus'orecordlogreadings.
At,thistime(approximately 0700)theShiftManagercameoutandaskedifconducting theShiftmeetingwouldbedistracting tous,ItoldhimthatmyselftheSTAandCR01wouldnotparticipate andwecouldstayfocusedontheapproachtocriticality sotheycouldconducttheshiftmeetingwithoutdistracting us.Ibelievethisanswerspage7paragraph (6).
aiWASHINGTON PUBLICPOWERSUPPLYSYSTEMPO.Box968~3000GeorgeWashington Way~Richland, Washington 99352-0968
~(509)372-5000At0705thereactorwasdeclaredcritical, IrecordedthereadingsinPPM3.1.2andthendirectedthereactorbeshutdowntoallrodsfullin.IwasunawareofthefactthatCRO3hadrecordederroneous readingsinthecontrolroomloguntilitwaspointedoutbytheNRCinspectors durinpmyinterview withthem.lrecordedthereactorcriticalatjx10fromSRMAmeteraadCRO3usedSRMDwhichreadlower(5x10)butrecorded5000insteadof50000whichIbelievewasjustamisprintonhispart.Thisanswerspage7paragraph (7).Icannotanswerpage7para(8)IwasunawareofthisuntilpointedoutbytheNRC,Icanonlysaythatthechartpaperwasintherecorderforsometimeandallourchartpapercomesinthesameboxes.ThisiswhatoccurredonJune27,1996duringthestartup,asbestasIcanrecall,Ibelievethatnoprocedural noncompliance occurred.
ThattheturnoveroftheCRSoccurredduringtheapproachtocriticality, wasunknownsincethereactor,theSTA,theCRO,northeSNE,evergaveanyindication thattheplantwasatthepointof"Approach toCriticality",
forhadthisbeenknownIneverwouldhavecommenced Turnover.
Thefailuretouseaconservative decisionmakingprocesscanbeputdirectlyonmefornotstoppingtheStartupwhenitwasveryclearinmymindthatwewouldachievecriticality priortotheMinimumAllowable Criticalposition, butasIhavestatedinthisletterandduringmyinterview withtheNRCIwantedthelogreadingsforapositiveindication ofabadECP.IfIcanprovideanyfurtherassistance Iwouldbehappytomakemyselfavailable toyouoranyoneelseformoreinterviews.
Respectfully yours;DonaldT.HughesJ To:BillPfitzer10/9/96From:SteveBerryIamwritingthisstatement atyourrequesttoanswersomeapparentdiscrepaaci~
documented intheNOVfortheCriticality thatwasachievedpriortothcminimumcalculated value.Iapologize ifmyleavingtheSupplySystemtopursueacareeratanotherUtilityhascausedanydifficulty withthisinspection.
AtyourrequestIhavelookedatpartsof,theNoticeofYiolation.
Itismyunderstanding theRobBarrhasstatedthatsomestatements madeinthisreportarebasedonatelephone discussion thathcandIhad.Thespecificareasofconcernaresections3through6.IwillrestatetheeventsasIrememberthemandthenaddressmytelephone conversation withRobBarrwithrespecttoNOVsections3through6.Iwilltrytothebestofmyabilityrecalltheeventsthattranspired onJune27,1996withregardtotheCriticality thatwa>>achievedpriortothecalculated minimumvalue.EventsonJune27MyfunctionoaJune27,l996wasthatoftheShiftTechnical Advisor.Iwasholdingoverfromgraveyard shifttodayshiftaspartofapreviously scheduled rotation.
IhadworkedcloselywiththeStationNuclearEngineers (SNEs)toassurethatthingswerereadyforthestartup,suchascontrolrodpullsheetsandamemodocumenting theminimumandmaximumcalculated criticality.
Ireviewedtheminimumandmax.valuesandensuredtheraaximumvaluewasdesignated inthepullsheets.TheminimumvalueiswithheldfromtheReactorOperators becauseofaGoodPracticefromINPO.TheCRSheldapre-jobbriefpriortnpullingcontrolrodsaspartofthektart-upprocess.Allofthcprecautions andlimitauons werediscussed iadetailaspartofthebrief,including ifcriticality wasachievedpriortotheminimumorafterthemaximumcalculated value.Wecommended pullingcoatrolrodsat-0315.InallcasescontrolrodmovementwasdirectedbythcCRS.TheCRSwasatthecontrolsformostoftherodpulls.Atsometimeheleftthecontrolsandsatathisdesk.Duringthistimehcwasstillmaintaining oversight ofmovingcontrolrods.Hesignedeachpullsheetwhentheywerecompleted andwcdiscussed wherewewereaklaracriticality.
lneverycasehedirectedtheROonthcaumberofrodstopullandwhentheROwasallowedtopulltherods.At-0640hrklinformedtheCRSandtheSNEkthatwewereapproaching criticality andthatwethatweneededthemattheP603.S~wnthereafter,theoneoftheSNEsandbothoftheCRSswereatP603.Itwasthenbroughttomyattention thatwewerenowhereneartheminimumestimated criticalposition.
Wediscussed thepossibility ofgoingcriticalpriortothemiaimumvalueandtheprocedural requirements tore-insert rodhinreverseordertoensurethefactorissubcritical.
writeaPER.andrequiredactionspriortocontinuing withstartup.Adiscussion washadastowhetherweshouldcontinueornot.Weagainreviewedthcprocedure forthedatarequiredtodocumentthecriticality (i.e.doublingtime,SRMlevels,etc..)aadwhowouldobtainit.Atthcdirection oftheCRScontrolrodOCT-14-1996 85:215155861615 t
.vithdrawal continued andthereactorwakdeclaredcriticalat0705hrs.Thcstepwaslessthantheminimumvalueandasrequiredbythestartupprocedure, thereactorwastakensubcritical atthedirection oftheCRS.Ihadnopriorknowledge thattherewasaconcernbyReactorEngineers aboutthecalculated ctiticalvalues.Myexperience inthepastwasthatthecalculated valuewaswithinafewstepsonthepullsheetfromtheactualstepthatcriticality wasdc,larrdd.
Wewercverypreciseandmethodical intheactionsthatweretaken.Ihadheardfrompeoplethathadbccninmanystartupsthatthiswasthesmoothest thattheyhadeverseen.ThoughIhadstatedthatwewereclosetocriticality at-0640hrs,itwasnotuntil25minuteslaterthatcriticality wasachieved.
NOVSection3IrememberthattherewasaproblemwithanIRM.Asstatedabove,atsometimetheCRSwenttohisdesk.Idonotrecallwhathewasdoingatthedeskordiscussing thisissuewithRobBarr.NOVSection4IdidnotifytheCRSthatwewereclo~togoingcriticalatabout0640hours.BoththedayandnightshiftCRSswereatthedeskatthetime.Therewasstillplentyoftimebeforecriticality wasachieved.
Thiswasnotanimminentnotification ofcriticality.
Wccontinually discussed wherewewereintheapproachtocriticality, whatcontrolrodswouldbemovednextandestimated thcimpactot'pulling thcnextrods(i.c.bigorlittleworth).Aftereachdiscussion, theCRSwoulddirecttheROonthcnextrodstopull.Irememberdiscussing withRobBanaboutmynotifying theCRSthatweweregettingclosetocriticality andthatatthattimehewasathisdesk.Soonthereafter,theCRSwasatP603andthediscussion aboutthepossibility ofgoingcriticalpriortotheminimumcalculated valueoccured.Ididnottellhim,thattheCRSdidnotstoptheirturnover.
ThercportimpliesthatROandmyselfwerepullingcontrolrodswithouttheoversight ofthereactivity manager.Theisdefinitely notthecase.Asdiscussed above,pullingcontrolrodswaspreciseandmethodical.
Nocontrolrodwaswithdrawn withoutthespecificdirection fromtheCRS.AturnoveroccunedbetweenthedayandnightshiftCRS>>occunzdwhilecontrolrodswerebeingwithdrawn.
Duringthisturnover, theywereinformedofthestatusofP603.Theywerctheonlyonesinvolvedinpullingcontrolrodsthatturnedover.TheROandmyselfwereholdingoverondayshifttocoverforabsences.
Wewerespecifically excludedfromturnoveractiviues.
TheShiftManagerconducted theshiftmeetingawayI'romF603sothatwe(CRSs,RO,SNEsandmyself)wouldnotbedistracted.
CRT-14-1996 85:2213135861615 NOVSectionSThereportstatesthatitwas"DuringtheCRSwalkthrough ofthecontrolboardpanels.thconcomingcontrolroomsupervisor suddenlyobservedthcconditions oftheplant...."
and"Thereactoroperatorstatedthatcriticality wasimminent."
IdidnotstateeitherofthesethingstoRobBarr.IdidstatethatsoonafterInotifiedtheCRSsandtheSNEsthatweweregettingclosetocriticalthattheycameuptothecontrolpanel,Ialsodiscussed thereviewoftheprocedure, thediscussion thatensued,andhowthedecisioncameabouttocontinuewithpullingcontrolrods.NOVSection6IdidtellRobBarrthatIreviewedtheletterfromReactorEngineering ontheestimated critical.
ThatIdidnotremcmbcrtheminimumvalueandthatitwasDonnyHughesthatraisedtomyattention thateventhoughwewereclosetogoingcritical, thatwewerenotasclosetotheminimumvaluethanhethoughtweshouldbe.Themaximumvalueisdocumented onthepullsheets.Theminimumvalueisintentionally keptfromtheReactorOperator.
Procedurally, ReactorEngineering isrequiredtoprovidetheestimated criticaltotheReactivity ManagerandtheSTA.TheSNEisprocedurally requiredtomonitorwhencriticality occursandthccalculated values.Itakeexception tothestatement that"assuch,didnotserveasabarriertoidentifyandinformthccontrolroomsupervisor oftheout-of-tolerance estimated criticalposition/criticaLity conditions."
Yes,tdidnottelltheCRSthatitwaspossiblethatcriticality wouldoccurpriortotheminimumvalue.Infact,theCRStold'me.ItisthepracticethatthcCRS,SNEandtheSTAallhavethemin./max.
criticalvaluesandthatwemonitorthemforcompliance withthestartupprocedure.
Inthiscase,IwasatP603verifying controlrodmanipulations.
Ididiiotthinkitappropriate tohavethememowithme,becauseIsatnexttothcROwhowasforbidden tohavetheinformation.
IalsoensuredthattheCRSandtheSNEwerewellawareofwhichstepwewerconinthepullsheetanddiscussed withthemwhcrcwcwerewithrespecttocriticality.
%Thattroublesmeaboutthewholewriteupisthatitimpliesthatwewercnotpayingattention towhatweweredoingandthatwewentcriticalpriortorealizing thatweexceededtheminimumcriticalvalue.Thisisinfactnottrue!IfIcanprovideanyfurtherinfornution, plcascfeelfreetocallme.StepenL.BerryOCT-14-19'26 85:~13135861615 NRCINSPECTION REPORT96-16,ADDITIONAL INFORMATION Attachment 4(Page1of1)Includedforyourreviewisavideocassette ofanall-employee
"TimeOut"conducted byPaulBemis,VicePresident, NuclearOperations onJuly23,1996.Inthe"TimeOut"Mr.Bemisaddressed thefollowing topics:Theimproving performance trendtheSupplySystemhasestablished overthepast2years.ThepositivecommentsofseveralNuclearVicePresidents visitingWNP-2toassessourperformance.
Thetworecentreactivity management events(criticality outsideECPandASDtestingtransient)
mayindicatealossofsafetyfocusTheimmediate corrective actionsafterthesetwoeventsweretostopalltestingandholdreactorpowerat65%,andtoestablish twoindependent seniormanagement teams;onetoassessourreactivity management program/measures, andasecondteamtoassesstheprocessandprocedures weusetoconducttestingoftheASDandDFWsystems.Finally,Mr.Bemiscalledforareturntothesafetyfocuswhichhelpedestablish ourimprovement overthelasttwoyears,andarenewedcommitment toeffective communication andtheteamworknecessary tomaintainourhighperformance standar NRCINSPECTION REPORT96-16,ADDITIONAL INFORMATION Attachment 5IRBREPORTCRITICALITY ACHIEVEDPRIORTOMINIMUMECP
VQSUPPLYSYSTEMSS2-IU'M-96-044 IXIXKOFFICE ME240&LNDUM nay:July2,1996FROM:WNP-2PlantManager(927M)ActingMana@Reactor/Fuel Engineaing Department (PE14)samzcr:lNCIDENTREVlEWARDREPORTFORPZK2964522,CRITXCALITY ACEHEVXZ)
PRIORTOMNIMUMZSTBCLTED CRHXCALPOSZXXON(ECP)
RzFzRzNcz:
1.PER296-0522PPM1.1.8Rev.5-IncidentReviewBoard3.IOMfmmBOC-12",datedJune26,1996.I"Estimated CriticalPosition(ECP)
forPER296-0522wasinitiated Thursday, June27,1996todocumentthatteactorniticality wasachievedpriortotheminimumexpeMpointcalculated bytheStationNuclearEngine=/SNE).
ThePlantManage:requested convening anIncidentReviewBoard(IRB)toinvestigate thedetailsoithisevent.Thismemorandum documents thecircumstances surrounding theevent,actionstaken,andrecommendations resulting iromthereviewperformed bythisIRB.IRB%members:
Manager,Reactor/Fuel Enme=ring (Citairman)
Supervisor, FuelDesignEngineering (LmiInvestigator)
Quality(Coominator)
ShiitManager,OvationsAllindividuals interviewed duringtheinvesti~on wereopen,candid,andwillingtodiscussallaspectsofthisincident.
TheShiitManager,ControlRoomSupervisors andStationNuclearEngine='rs involvedunderstood weHtheirresponsibilities withrespecttoReacuvity Management andhaveinternaiized thesignificance oftheevent.INCID~DCRIFFION:
PPM1.3.59Reactivity Management Program"requiresthatanECPcalculation beperformed bytheSNE,andbeprovidedtotheCRSpriortoinitiating rodwithdrawal.
Anace~table bandof-.'%MisappliedtotheECPtoaccountforcalcuiationai unce~nties.
IfthecoreMstogocriticalwithinthisbandthenthereactorismade/maintained subcriticai umiladetermination ismadetharexplainsthedeviation.
Page1of8WP102Ad~l ITuesdayevening(June 25),thenightshiftSNEpreparedtheECPcalculation basedonaprojected startuptimeof0600June26.HeusedthecoldoptionsfoundinthePREDICTmoduleofPOWERPLEX toperformhiscalculations.
HepreparedandissuedanIOM(Reference 3)whichstatedhisassumptions andcontained theECPanditsacceptance band.TheSNEnoticedthathiscalculated ECPwassignificantly different thanthepointwherecriticality wasachievedduringthefirstcriticalthiscycle.TheECPwasseveralstepslaterinthepullsheets indicating alessreactivecore.Heexpectedashif'tinthatdirection duetotworeasons:1)thepresenceofincreased poisoninventories associated withtheshortbutsignificant timeatpower;2)theECPhadtoincludeonefullyinsertedin-sequence inoperable controlrod.However,themagnitude ofthechangewaslargerthanheexpectedbasedonexperience.
Therefore, herequested thedayshiftSNEandSNEintrainingtoinvestigate andindependently calculate andvalidatehisanswer.Duringthedayshift,June26,thedayshiftSNEsrepeatedtheECPcalculation andexploredthesensitivity tothemoderator temperature assumptions asweQastimesinceshutdown.
Theanswersobtainedwereconsistent withthedocumented calculation andnosignificant differences werefound.Therewasaneffort~boneoftheengineers touseanalternate approachtoestimatetheECP.Hepredicted RWMstep9-1basedonthecold(68'F)cleanrodworthtablescontained intheCycle12StartupandOperations Report.AlthoughthisanswerhappenedtobeclosertotheBOCcritical(step 7-3),itcouldnotbeusedbecauseitdidnotcorrectly accountfortheoutofsequencerodandtheeffectofaccumulated poisons.Stillnotsatisfied, Wednesday afternoon around14:00,theengineers fromReactorEngineering soughthelpbycontacting membersoftheFuelDesigngroup.OneFuelDesignen~axwasaskedtoindependently evaluatetheECPusingthedesigncodeSIMULATE.
Heproceeded toupdatetheSIMJLATEmodeltocatchupwiththecoreburnupconditions atplantshutdown.
Inthemeantime, atapproximately 15:30,anotherFuelDesignenginerwasaskedtoestimatetheresidualworthofXenongiventhecyclepowerhistory.Usingapointmodelheestimated theworthtobeapproximately 0.5%~Herecognized thathisanswerwasinconsistent withthePOW12&LEX resultsandrecommended additional investigation.
SincehewasnotlamiliarwithPOWEIVLEX heaskedtheotherFuelDesignengineertocontinuetoinvestigate.
TheReactorEn~eering Supervisor, whowasalsothenightshiftSNE,calledaround15:30andrequested thattheinvestigation focusonrepeating thePOVFEZPLEX calculation independently.
Therefore theFuelDesignengineerwhowasworkingontheSIMJLATEmode1,switchedeffortstocomplywiththisrequest.UsingPOWER'LEX, theengineerstartedfromtheBOCconditions, recreitedtheexposurehistoryandanalyzedtheECPconditions.
Thisindependent evaluation arrivedatresultsconsistent withthoseofReactorEngineering.
Then,theFuelDesignengine@wentbacktoworkonhisSIMULATEmodel.HeanalyzedthePOWEZPLEX predicted criticalconfiguration usingSlhHJLATE andobtainedaresultwhichwas0.6%rXearlierthanPOWERPLEX.
Thedifferenc=
betweenthetwocodeanswerswaswithinexpectedrangebasedonexperience.
Whenatpower,coreconditions aretrackedon-lineautomatically byPOWER'LEX.
Ontheotherhand,theSIMJLATEmodelmustmanuallybeupdatedatmuchcoarsertimestepsandtherefore differences ofthismagnitude arenotunusual.Page2of8WP102AOf6OOI
~~TheFuelDesignengineersharedtheresultsofhisinvestigation andconsulted overthephonewiththeFuelDesignengineerwhohadearlierestimated theXenonworth.Basedonthisdiscussion, hesoughthelpbycallingtheComputerEngin~gLeadwhosuggested lookingatthecodeswitchesfortheSamarium/Promethium aswellastimedependent Xenon.Theswitchesappearedtobesetcorrectly.
Hethencommunicated theresultsandextentofhisinvestigation totheReactorEngin~gSupervisor(night shiftSNE)andleftthesiteat21:00.TheReactorEngineering Supervisor determined thecodeanswertobeacceptable.
Hisdecisionwasb~ontheresultsoftheinvestigative workthathadtranspired duringthedayandthebetthatthreindependent POWER'LEX evaluations oftheECPhadgivenconsistent results.AsSNE,hedelivered acopyoftheIOMtothenightshiftSTAandtotheShiftManager(Reference 3).TheSTAdidnothaveenoughexperience withcriticalpredictions toformabasistochallenge thevalidityoftheECP.Herevieweditandplacedhiscopyoutofsightknowingthat,byprocess,theROonthepanelisnotsupposedtoseetheECP.TheShiftManagerhadabriefdiscussion withtheSNEabouttheECP.Basedonexperience, theShiftManagerquestioned thereasonableness oftheECP.TheSNEdiscussed thelevelofscrutinythathadtranspired duringtheday.Aftertheexplanation, theShiftManagerfeltsatisfied basedonthethoroughevaluation performed.
TheShiftManagergaveacopyoftheECPtotheCRS.ThiswastheCRSfirstexperience withECPs.AstheReactivity Manager,theCRSfocusedoncoachingtheROontherequirements ofPPM3.1.2andPPM1.3.1toensurethatrodpullstocriticality wouldproc~inafaultless mannerandthatallprocedural expectations wereclearandfollowed.
Hisreviewincludedtheactionsassociated withtheECPandwhattodoifthecriticality isnotexperienced withintheexpectedband.RodPuQscommenced at3:15AMonJune27,1996.TheSNEandtheCRShadashiftchangeat6:00AM.TheROonthepanel,theSTA,andtheShiftManagerwereholdingoveruntil10:00.TheoutgoingCRSfeltthatatthetimeofcommencing turnovertherewerenoindications thatcriticality wasimminent.
Thiswasconfirmed bythedayshiftSNEwhoonturnoverhadreviewedSRMcountrateonthebackpanelsandfoundthembetween200and500CPS.Atapproximately 6:40theSTA,whowasperforming assecondverifierforcontrolrodmoves,toldtheCRSthatitappearedthattheyweregettingclosetocriticality.
TheCRSrecognized thatwemaybegoingcriticalsoonerthanpredicted'by ECP.Therequiredactionwasclearinhismindbutheconsulted thePPM3.1.2guidanceagain.Theon-coming CRSassumedtheshiftatapproximately 0645.AtthattimetheROonthepanelandtheSTAhadinformedhimthattheywereveryclosetocriticality.
Bothon-coming andoff-going CRSsconsulted withtheSNEandconcluded thattheywerelikelygoingtomisstheECPwindowandthiswouldrequireashutdown.
TheSNEdidnothaveasafetyconcernsinceshutdownmar~hadbendemonstrated atBOCandtheywerebeyondthepointwherethecorehadgonecriticalatBOC,indicating alessreactivecoreasexpected.
TheSNEinanticipation that'they maygocriticalpriortotheminimumpoint,initiated actionstoretrieveafreshsetofpullsheets tosupporttherequiredshutdown.
Page3of8WP102ROt&OOI Discussion andconsideration wasgiventowhetherrodwithdrawal shouldbecontinued.
Theon~mingCRSdiscussed thesituation withtheShiftManagerandreviewedPPM3.1.2.Basedontheprocedural
~~guidance{PPM 3.1.2)andconsidering thatthiswasawellcontrolled evolution thedecisionwasmadetoproceed.Theoff-going CRSremainedintheControlRoomuntilthereactorwentcriticaltoassistasnecessary.
Atapproximately 7:05AMthereactorwasdeclaredcriticalonrod18<7atposition26(RWMstep8-3).Thisoccurredpriortoreachingtheminimumallowable ECPpositionandtherefore requiredashutdowntoinvestigate.
IIVIIVKX)TATE ACTINTAKEN:At7:12AM,underthedirection oftheCRSandfollowing guidancefromtheSNE,controlrodinsertion was'nitiated toshutdownthereactor.ActionwastakenbytheSNEtocontacttheReactor/Fuel engineringManager,theReactorEngineering Supervisor andtheFuelDesignSupervisor torequestassistance.
Rodinsertion continued untilallbutGroup1rodswerefullin.Eventually aQtherodswereinsertedby10:00AM.Actionwasinitiated bytheReactorEngine=ring andFuelDesign~upstoinvestigate thecauseoftheerrorintheECPaswellasthehumanperformance aspectsoftheincident.
PER296-0522wasinitiated andanIRSconvened.
Atapproximately 11:00AMtheIRBinvestigators commenced takingstatements andinterviewing personnel involvedtodetermine thesequenceofeventsandotherinformation whichledtothisincident.
BythistimetheerrorintheECPhadbe=ntracedtothefactthatthePOLLEXcalculations hadnotcorrectly depletedXenonasintended.
TIAONVERVIEWWrittenstatements wereobtainedfromtheShiftManager,CRS,STA,SNE,andSNE-in-training thatwerepresentduringthecritical.
Thesepersonnel aswellasothe<werealsointerviewed foradditional details.Applicable procedures wereidentiQed andreviewed.
TheseincludedPPM1.3.1,1.3.59,and3.1.2.Theconductofthecontrolroompersonnel canbecharacterized asexemplary, asallparticipants werewellfocusedonperforming thereactivity manipulations inawellcontrolled professional manner.Strictadherence toprocedures wasmaintained andreinforced bysupervising personnel, consistent withstationpolicy.Whenpersonnel wereaskedwhythedecisionwasmadetocontinuetothepointofcriticality, acontributing factorwasbasedonliteralprocedural compliance.
Step4.2.5ofPPM3.1.2said:"Ifcriticality occursbeforetheMinimumAllowable CriticalPosition, stopcontrolrodwithdrawal andnotifytheCRS.TheCRSshoulddirecttheCRQtodrivecontrolrodsinthereverseorder.TheSNEprovidesarodpatternthatmaintains thereactorsubcritical."
Page4of8WP102AIl6OOI Thisimpliedthatanadequatestoppointwasatthepointofcriticality.
Althoughtherewere40stepsremaining toreachtheminimumpoint,theywereperforming stepsofrelatively lowworthsoitwa'ossible togetclosertothetarget;Reactorcriticais havebeendonewithoutECPspreviously.
TheBWROGReactivity ControlsReviewCommitte=
considers theuseofECPsasoptional.
Therewasnosafetyissueassociated withthiscritical.
Inhindsightitwouldhavebeenoptimumtostopandshutdownpriortocriticality, onceitwasrecognized
'hattheECPhadaproblem.However,withrespecttoReactivity Management, conservative actionswerealreadyprescribed intheprocedure.
TheseincludehavinganECPandtakingconservative actionsifcriticality isexperienced outsidetheacceptable band.Inshutting.
downthereactorafterreachingcriticality priortotheminimumaQowableECP,theSNEprescribed anadequatestoppingpointthatwouldprecludeinadvertent criticality.
Thiswasconsistent withtheprocedural guidance.
Thenafterconsultation withmanagement itwasdecidedtodrivetoallrodsfullyThequestioning attitudeoftheReactorEngineers wascommendable astheypursuedcorroboration oftheECPbyindependent evaluations.
Notsatisfied withtheanswer,theyinteracted andrequested te"hnical supportfromother~ups.Goodteamworkwasdisplayed.
Itisunfortunate thattheproblemwentundetected despitethesignificant analytical effortundertaken.
Itseemsthattheeffortfocusedondemonstrating thattheECPwascalculated correctly andcredibleinsteadoffocusingonwhatcouldbewrongwiththecode.Inhindsight, theengineering personnel involvedrecognize thattheirtechnical andhumanperformance, althoughwellintended, wasunsatisfactory astheyfailedtouncovertheerrorincodeuse.Management involvement duringtheECPinvestigations waslimitedtotheActingSupervisor ofReactorEngineering.
Hecorrectly triedtoinvestigate theconcernusingavailable engint=ring resources.
Hisjudgement toproc'ased ontheavailable evidencewaslessthanoptimum.Furtherappropriate conservative actionswouldhavebe=ntoinvolvetheManagerofReactor/Fuel Engineering wheneve.questions ofthisnaturearise.Similarly, theSupervisor ofFuelDesignshouldhavebeencontacted.
TheReactor/Fuel Engineering ManagerandtheSupervisor ofFuelDesigncollectively addressed thedepartment personnel duringaTimeOut.Theneedforconservative actionswhenquestions arisewasreemphasized, including stoppingevolutions wheneverexpectations arenotmet.Theneedforimprovedcommunications withmanagement wasalsodiscussed.
\ECPERRRPECIFICSTheerrorintheECPwastzacedtoselecting thewrongXENONDEPENDENCE optioninPOWERPLEX whentheCOLDcdticalcaseswereanalyzed.
AnupgradedversionofPOWER'LEX wasinstalled duringthelastoutage.Thiswasneededtoincorporate theABBfuelCPRcorrelation aswellasABBfuelpreconditioning rulesandthermallimits.TheupgradedversionofPOWER'LEX includedSiemenslateststandardversionofthesoftwarepackage.Thischangecontributed directlytotheevent.POWERPLEX nowhastwooptionsfortimedependent Xenon.Theseareselectedbysettingtheselection Page5of8WA102AdId.ddl flagto-1or0.Basedonthisflag,thecasewilldepleteXenonbasedontherestartfile"previous" powerlevel,orbasedontheinputfile"current" powerlevel.Thedefault,optionissetto-1asthisisthecorrectsettingfortheMONITORon-lineruns.Thisoptionisalsonormallyusedforperforming HOTPREDICTcases.Bothoptionswillprovidetimedependent XenonforHOTcases.However,forCOLDcases,the-1optiondoesnotconsidertheoutagetimeandwillnotdepleteXenoncorrectly.
ForCOLDcasestheflagneedstobesetto0.DuringPOWHG'LZX softwaretesting,thePOWER'LEX systemadaunistrator noticedthattherewerenowtwochoicesforXenondependence.
Hecontacted theSiemensPOWERPLEX softwareengineerforguidanceonwhichoptiontouse.TheSiemenssoftwareengineerrecommended toalwaysusethedefaultflagof-1.Infact,thePOWIM'LEX UsersManual(EMF-1886P)
issuedbySiemenscontained twoexamplesofCOLDcriticalcalculations wherethefagwasincorrectly setto-1.Thisinteraction withSiemenspersonnel contributed tothisevent.~rtheevent,adifferent Siemenssoftwareengineer(the MICROBVRN custodian)
wasconsulted andheconfirmed thatonlythecasewheretheflagissetto0wouldworkco~yforCOLDECPcalculations.
Attachment 1showshowtheflagwassetinthepreviousversionofPOWER'LEX(there wasonlyoneTIMEDEPENDENT Xenonoption).Attachment 2showsthecurrentversionwiththeadditional optionflag.TheSNEsusedtheSiemensoriginalrecommendation asthebasisforflagselection.
Becausethiswasthedefaultsetting,theerrorincodeusewasrepeatedinallthreeindependent ECPevaluations.
Havingthe-1asthedefaultcontributed tothisevent.Armedwiththenewunderstanding, ECPswererecalculated showingexcellent ammmentwiththeactualcritical.
TheSNEslackofexperience usingthenewoptionscontributed tothisevent.ThenewversionofPOWEZPLEX softwarewastestedrigorously byfollowing theInstallation Acceptance TestProcedure(IATP)
providedbySiemens.TheSiemensIATPwassignificantly augmented bytheSupplySystemPOWXZPLEX administrator andincorporated intoPPM9.3.31.Thistestexercised thedifferent optionsbutfailedtodetectthesubtledifference.
TheCOLDtestcasesweredoneatBOCwherenoXenoninventory existsanddifferen~
arenotexpected.
TheIATPtestingpaidparticular attention todifferences betweentheoldandnewversion.Softwaredeficiencies identified inthepreviousversionweretestedtoensuretheywerenotreintroduced.
Newfeatureswerealsotestedtoensuretheymetfunctional requirements.
Theamountoftestingassociated withthisinstallation waswellinexcessofanyprevioustestingefforts.TheSNEsreceivedformaltrainingonthenewPOWERPLEX system.Approximately threehourswerespentreviewing changesinthecode.Itwaspartlychangemanagement andSNErefresher.
Thetrainingfocusedmoreonchangesinthewayinformation ispresented totheuser,changesinthermallimitsPage6of8WA102hdl6.00)
nomenclature, newpreconditioning rules,etc.,butdidnotincludehowtousethePREDICTmoduleforcalculating ECPs.Thetrainingdid.notincludeexplaining thedifference betweenthetwoTIMEDEPENDENT Xenonoptions.Thismayhavebeenacontributor totheevent.Calculation ofECPsiscuzrently considered skinofthetradeandassuchrequirestrainingaspartoftheformalSNEQualification Program.Thereiscurrently noprocedural guidancedescribing howtocalculate theCOI.DECPcases.TheSNEhasavailable thePOWERPLEX UsersManualwhichcontainsdetailsandguidanceonhowtoexercisethedifferent useroptions.Adraftprocedure wasdeveloped yearsagobutwasneverfinalized orimplemented.
ThelackofaformalECPcalculation procedure isnotconsidered acontributor tothiseventbecausethesameanswerwasindependently calculated byatleastthreedifferent individuals withoutaprocedure.
Theprocedure wouldhavelikelycontained thevendor'srecommendations whichwereinerror.However,thereshouldbeaprocedure toensureconsistent andcorrectapplication ofthecode.Theprocedural
@cdancefoundinPPM1.3.59andPPM3.1.2wasconsidered conservative.
However,enhancement tothisguidancewasrecommended toemphasize thattheoperating crewshouldstoprodwithdrawal andturnaroundiftheyweretoanticipate thatcriticality isgoingtobeachievedpriortotheminimumallowable point.Meprocedures wererevisedtoincludethisenhancedguidance.
AnewECPwascalcuhted byReactorEngintringusingthecorrectXenoni%MEDEPENDENT flag.Anindependent ECPcalculation wasgenerated bytheFuelDesignusingtheSIMULATEcode.Bothindependent methodspredicted RWMstep7-1astheECP.APOCreviewoftheincidentwasconducted themorningofJune28,1996.POCreviewedthenewECPandthenatureoftheprocedural enhancements andapprovedrestartoftheplantbasedonthefindingsandcorrecave actionsimplemented.
AgeneralstationTimeOutwasdeclaredtobeheldpriortoplantstartup.Thepurposeofthetimeoutwastoreviewtherecentnegativetrendinhumanperformance errorsthathavebenexperienced overthelasttwoweeks,including thisevent.Theemphasiswastoremainfocusedonthejobathandpayingattention todetailandtoworkasateamtohelpeachotherturnaround thistrend.Additional rootcauseandcorrective actionsareexpectedtoresultfromthenormalPERresolution process.IRBRECMVKNDATIN:Inadditiontothecorrective actionsalreadytakenthefollowing additional recommendations areofferforconsideration:
TheECPcalculation processshouldbeincludedinaprocedure.
Thiswillensureconsistent application ofthePOWER'LEX code.2.Theevaluation ofalldifferences introduced bythenewversionofPOWER'LEX shouldberevisited toensurethatsimilartrapsdonotexistinotherareasofthesoftware.
Page7of8
~~3.4IssuealettertoSiemensexplaining thesigniiicance oitheeventandrequesting anexplanation.
Requestthattheyissuecorrections tothePOWERPLEX UsersManual.Requestthattheyevaluatethenevitoinformtheirothercustomers aboutthisevent.Itispossibletoprovidetoolstoanalytically estimatehowclosetocriticalthereactoris,basedonsubcritical multiplication.
Investigate andevaluateindustrypracticetoexplorethepossibility ofimplementing alternate meansofmonitoring theapproachtocriticality atWNP-2.5.Anevaluation oftheReactor/Fuel Engineering personnel humanperformance issues,bothnegativeandpositive, shouldbecompleted.
Theseinclude:a)Discussions ofpe~nnelperformance issuesbothnegativeandpositiveshouldbedocumented intheperiormanc=
evaluations oftheindividuals involved.
Evaluating theeff~oithesequenttiirnover oftheReactorEnginmnng Supervisor andpotential impactontheconsistency andqualityofsupervision.
c)ThepracticeofhavingtheSupervisor ofReactorEngineering alsoworhngonshiftasanSNE,mayhavereducethesupervisory performanc=
level.Thisptacticshouldbeevaluated foranalternate approach.
6.Includediscussion ofthiseventandlessonslearnedinthenextSNEcontinued trainingsession.
Attachment:
1.~tofoldPOWER'LAC vision22.EditoinewPOKBPLZCversion3.PER296-0522DISTREUTIO¹ 9270PE14PE14PE16PE219270PE14PE1692709270PE14PE1492709270PM1PE?1WNP-2Files964YWP102IlO~lPage8of8
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..Quarttycbncu g1,gAg2~,gGQSafetyRebttedQASM'hd.HNAgNAO7Comments(tnctudal SeaResolution Forminsttuctfons forinformation toinctudeinthissection)~'...~...,~a)Duringreactorstartup9642,theminimumestimated criticalpositionbandwasnotachievedpriortoreactorcriticality.
ThereactorwentcriticalatRWMstep8-3TheMinimumallowable criticalpositionwascalculated tobeRWMstep11-12ThereactorwasshutdownperPPM3.1o2andaninvestigation toresolvethediscrepancy wasinitiated I,eb)Disposition andequipment classification aremarkedN/Abecausethiswasaproblemassociated withamiscalculation ofthe'stimated criticalposition(ECP).ECPsarepartoftheprogramatic controiofreactivity andnotpartofanyequipment ve,c)PTLsearchfoundPTLH42085,No~e(ncCriticality duringSeginning ofCycle8startup.Passportsearchisnotapplicable forengineering calculation errors.Noequipment failed.Id)ActionsforH-92085resultedinfuturestartuppullsheets havingnotchworthsreducedtoevencoreresponsiveness.
e)TheeventoccurredduetomisuseofthePOWERPLB(
predictive options.Acontributing causewasthatmajorchangestothePOWERPLEX codeduringtheR12outagewerenotfullyevaluated foruseafterbeginning ofcycle.f)Thepotential forsimilarerrorstooccurispossibleeverytimecodechangesaremade.Codetestcasesshouldbeevaluated formultipleconditions todetermine effectiveness.
Codechangesshouldbepresented intrainingsessionstoappropriate personnel.
QCol)tinued 609RCAReportRaquited gYesQNo8QV4g@p)NJ9xG Q11~~)ISqt~QpERotspostutngdtanagartpnntilsignatuteIOata QtsANI(pnntYStgnatute/Dstd Q14pOCteviawrequinsfpriortottnptementtng InterimActionsQYesQNoPQCreviewrequiredpriortodacaringopeyabslily Q.YesQNoQtsEf)gtt)eentlg CCNICunenoe (PnntPSlgnatunSIOata Q16Quality(pnnt)lslgttatuteIDate
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Numbepofpant)anent dtsposttfon Conective Actions11.',;+AN1itUnknown(UNKN),JustifyaboveQAssumedRhk(AR01),Justifyabove'VettafCommunication (PEDt),QWorkPraa5cs{PE02),QWcmgdnduh(PEQS),
gWrhhmpnmedures andQocummas(pR01),(7.Ergonomics (EQol),QComslarmorEnvionnrmn (Eaos),Qlhskmconsgure5on andAnalysis(Eaos),QSpedsmomMmuracruia Cenurncgcn (Ease),QMdmenanmiymmg (Ease),Qpnmlu)mem Qperuucn(EQOS),Evummllrrlluence (Eko1).gyrchhgrarmginas gaol),os.5V(o5QworlrQrgenaason(Planning goM01),gSupuviemymehoas(MM02),
1>()(gCrnngeManagemnu (MM(a),gResourceMarngemenl (MM04),02QManagerhl Melhais(MM05),96tt-29231 RS(1/96)1.3.12A1.Engineering concuttence shouldbeobhsinedpriortoimplementation ofPERiy)tetfyn disposition forsafetytetatadequipment.
2.Engineering concunence shouldbeobtainedpriortodctarit)g safetyrelatedaquipnuutt opetabte.
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